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Experimental Investigation of lifting phenomenon in Sediment-Laden Density Currents | ||
| تحقیقات مهندسی سازه های آبیاری و زهکشی | ||
| Article 10, Volume 17, Issue 67, March 2017, Pages 129-144 PDF (1.04 M) | ||
| Document Type: Original Article | ||
| DOI: 10.22092/aridse.2017.109613 | ||
| Authors | ||
| Peyman Varjavand* 1; Mehdi Ghomeshi2; Ali Hosseinzadeh Dalir3; Davood Farsadizadeh3 | ||
| 1Research assistant professor of agricultural engineering research department, Khuzestan agricultural and natural resources research center, AREEO, Ahwaz, Iran | ||
| 2Professor, Faculty of Water Science Engineering, Shahid Chamran University of Ahwaz, Ahwaz, Iran | ||
| 3Professor, Department of Water Engineering, University of Tabriz, Tabriz, Iran | ||
| Abstract | ||
| Density currents are formed when gravity acts upon a density difference between two different fluids. These currents are the most important transport mechanisms and deposition of noncohesive sediments in narrow and deep reservoirs. In this research, 63 experiments were performed to investigate the effects of two shapes and three heights of artificial roughness on sediment-laden density currents. Velocity and concentration profiles were measured in the body of current. Results showed that presence of roughness causes 47% increasing in the density current body thickness, 29% decreasing in the maximum value of velocity and 163% increasing in the distance of peak value of velocity point from the bed in the normal velocity profile. Also for different roughness and with special hydraulic conditions, Lifting phenomenon has been observed, which is affected by densimetric Froude number, relative roughness and blockage factors. This phenomenon effects on the velocity and causes 5-25% increasing in the maximum value of velocityi the stream line of current. Sedimentation rate in the current over rough bed is approximately 223% more than smooth bed if lifting phenomenon has not be occurred. | ||
| Keywords | ||
| Artificial rough bed; Lifting phenomenon; Sediment-Laden density current; Sedimentation rate; Velocity profile | ||
| References | ||
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